Process for the manufacture of alkyl vanadates

Abstract

The yield of alkyl vanadate formed by the reaction of vanadium pentoxide and an alkyl alcohol in the presence of an azeotroping agent and, preferably, a catalyst is improved by the present invention. It involves lowering, prior to the reaction, the amount of vanadium having a valence lower than +5 in the vanadium pentoxide reagent.

What is claimed: 
     
       1. In a process for the manufacture of alkyl vanadates by the reaction of vanadium pentoxide with an alkyl alcohol in the presence of an azeotroping solvent to assist in the removal of by-product water, wherein the improvement comprises lowering in the vanadium pentoxide to be reacted, prior to the reaction, the amount of vanadium having a valence of lower than + 5 in order to achieve an increased yield of alkyl vanadate formed by the reaction. 
     
     
       2. A process as claimed in claim 1 wherein the azeotroping solvent is an alkane solvent. 
     
     
       3. A process as claimed in claim 2 wherein the solvent is heptane. 
     
     
       4. A process as claimed in any of claims 1-3 wherein the reaction is carried out in the presence of an effective amount of a catalyst. 
     
     
       5. A process as claimed in any of claims 1-3 wherein the reaction is carried out in the presence of an effective amount of a basic nitrogenous catalyst. 
     
     
       6. A process as claimed in any of claims 1-3 wherein the reaction is carried out in the presence of an effective amount of a basic nitrogenous catalyst and the amount of vanadium having a valence lower than +5 is lowered to no more than about 0.2%, by weight of the vanadium pentoxide. 
     
     
       7. A process as claimed in any of claims 1-3 wherein the reaction is carried out in the presence of an effective amount of a basic nitrogenous catalyst, the amount of vanadium having a valence lower than +5 is lowered to no more than about 0.2%, by weight of the vanadium pentoxide, and the alkyl alcohol contains a C 2  -C 6  alkyl group. 
     
     
       8. In a process for the manufacture of alkyl vanadates by the reaction of vanadium pentoxide with an alkyl alcohol in the presence of an azeotroping solvent to assist in the removal of by-product water, wherein the improvement comprises conducting the reaction using vanadium pentoxide containing a lowered amount of vanadium having a valence of lower than +5 in order to achieve an increased yield of alkyl vanadate formed by the reaction. 
     
     
       9. A process as claimed in claim 8 wherein the azeotroping solvent is an alkane solvent. 
     
     
       10. A process as claimed in claim 9 wherein the solvent is heptane. 
     
     
       11. A process as claimed in any of claims 8-10 wherein the reaction is carried out in the presence of an effective amount of a catalyst. 
     
     
       12. A process as claimed in any of claims 8-10 wherein the reaction is carried out in the presence of an effective amount of a basic nitrogenous catalyst. 
     
     
       13. A process as claimed in any of claims 8-10 wherein the reaction is carried out in the presence of an effective amount of a basic nitrogenous catalyst and the amount of vanadium having a valence lower than +5 is present at no more than 0.2%, by weight of the vanadium pentoxide. 
     
     
       14. A process as claimed in any of claims 8-10 wherein the reaction is carried out in the presence of an effective amount of a basic nitrogenous catalyst, the amount of vanadium having a valence lower than +5 is present at no more than about 0.2%, by weight of the vanadium pentoxide, and the alkyl alcohol contains a C 2  -C 6  alkyl group.